Relevance of the Study of Interlanguage to Teaching Efl at the Tertiary Level

Introduction
A second/foreign language learner takes a linguistic journey from his/her mother tongue to the target language and naturally constructs a personal linguistic system in the interim time. This individual system is termed ‘interlanguage’ (Selinker 1969, 1972), ‘approximative system’ (Nemser 1971), ‘transitional competence’ (Corder 1967), or ‘idiosyncratic dialect’ (Corder 1973). In a narrower sense, interlanguage refers to the intermediate status of the second/foreign language learner’s system between his/her mother tongue and the target language. In a broader sense, it stands for the second/foreign language learner’s present knowledge of the language he/she is learning (Spolsky 1989). In a general sense, interlanguage is defined as ‘the interim grammars constructed by the second-language learners on their way to the target language’ (McLaughlin 1987:60).